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Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
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Volume 22, issue 5 | Copyright
Hydrol. Earth Syst. Sci., 22, 2689-2703, 2018
https://doi.org/10.5194/hess-22-2689-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 07 May 2018

Research article | 07 May 2018

Predicting groundwater recharge for varying land cover and climate conditions – a global meta-study

Chinchu Mohan1, Andrew W. Western1, Yongping Wei2, and Margarita Saft1 Chinchu Mohan et al.
  • 1Department of Infrastructure Engineering, University of Melbourne, Melbourne, Victoria, Australia
  • 2School of Geography, Planning and Environmental Management, The University of Queensland, Brisbane, Australia

Abstract. Groundwater recharge is one of the important factors determining the groundwater development potential of an area. Even though recharge plays a key role in controlling groundwater system dynamics, much uncertainty remains regarding the relationships between groundwater recharge and its governing factors at a large scale. Therefore, this study aims to identify the most influential factors of groundwater recharge, and to develop an empirical model to estimate diffuse rainfall recharge at a global scale. Recharge estimates reported in the literature from various parts of the world (715 sites) were compiled and used in model building and testing exercises. Unlike conventional recharge estimates from water balance, this study used a multimodel inference approach and information theory to explain the relationship between groundwater recharge and influential factors, and to predict groundwater recharge at 0.5° resolution. The results show that meteorological factors (precipitation and potential evapotranspiration) and vegetation factors (land use and land cover) had the most predictive power for recharge. According to the model, long-term global average annual recharge (1981–2014) was 134mmyr−1 with a prediction error ranging from −8 to 10mmyr−1 for 97.2% of cases. The recharge estimates presented in this study are unique and more reliable than the existing global groundwater recharge estimates because of the extensive validation carried out using both independent local estimates collated from the literature and national statistics from the Food and Agriculture Organization (FAO). In a water-scarce future driven by increased anthropogenic development, the results from this study will aid in making informed decisions about groundwater potential at a large scale.

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To ensure a sustainable supply of groundwater, scientific information about what is going into the system as recharge and what is taken out of the system via pumping is essential. This study identified the most influential factors in groundwater recharge and developed an empirical global recharge model. The meteorological and vegetation factors were the most important factors, and the long-term global average recharge was 134 mm per year. This model will aid in groundwater policy-making.
To ensure a sustainable supply of groundwater, scientific information about what is going into...
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